You said you can make it so that it simply duplicates your desktop but you can't find an option for stretching it right and not just no image at all coming up?
On my moms laptop I can acquire what you are looking for by right clicking on the desktop>Properties, click the settings tab, and then the Advanced button. From there you click the 'Displays' tab and it should show a power on and off button for the extra monitor and whatnot, make sure that it is indeed turned on and it's monitor 2. Now go back to the Settings tab and if that checkbox EXTEND MY WINDOWS DESKTOP is still not there, then try changing the pull down menu above it where it says "Displays" to "Multiple Monitors".
Sorry if I had a bad explination, but it's kinda hard without being there.